3.Laboratory Studies in Chemistry by Robert Hart Bradbury (1912)"Filter the sodium hydrogen carbonate and dry it between folds of manila paper.
... (6) Transformation of sodium hydrogen carbonate into sodium carbonate. ..."

4.Laboratory Studies in Chemistry by Robert Hart Bradbury (1912)"Filter the sodium hydrogen carbonate and dry it between folds of manila paper.
... (b) Transformation of sodium hydrogen carbonate into sodium carbonate. ..."

5.Outlines of Inorganic Chemistry by Frank Austin Gooch, Claude Frederic Walker (1905)"Solvay, a Belgian, depends upon the fact that sodium hydrogen carbonate is but
slightly soluble in a cold ammonia solution of common salt. ..."

6.The Chemical News and Journal of Industrial Science (1908)"The separation of the chromium, vanadium, and uranium, which are present together
in the filtrate from the sodium hydrogen carbonate precipitate, ..."